Principle And Operational Working For Electronic Drum Level Indicator

Dunno. What did the manufacturer say when you called?

Google: three element drum level control

Do some basic research, on your own!

Then, you will posses knowledge, not just questions.

Here's a start:

Electronic Drum Level Indicator - YouTube

I hope this helped you, as much as it did me.

https://www.google.co.za/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CCsQFjAA&url=http%3A%2F%2Fwww.clarkreliance.com%2Fsite%2Fapplications%2FDocumentLibraryManager%2Fupload%2FBoilerLevelGuideBook01.PDF&ei=DH_QVJHHEeKV7AaJ74GACA&usg=AFQjCNHpgqGbiWKDn6DC9Y5TU5WeAeZLqw&bvm=bv.85076809,d.d24

Thank you Hilton

Your'e welcome!

It's all pretty much based on light, mirrors, and transmission of said light through the column of either steam or water in a gauge glass of a boiler. If the water is present, one source ( typically red ) will be transmitted through for that "bulb", and if not, then the other one (typically green) will transmit through. It tells approximate water level in the steam drum without having to go physically look at the gauge glass.

The other way to do this is with a calibrated differential pressure gauge where one leg is full to the normal top attachment for where a gauge glass would be, and the other is direct coupled to the bottom level of said gauge glass port. The difference in column pressures is XMT to the control room, and the HMI sorts it out as to what that means in terms of boiler level, as in -12, 0, or +8.

The Hydrastep uses conductivity to determine the water/steam interface. I work at Emerson, so let me know if you need anything more on this device.

Thanks Lydia..

Yarway apparently offers the same electronic remote sensing of boiler drum level by conductivity probes, and also still offers the optical version of this also.

You are welcome.

There is also a short animation that shows how the hydrastep displays the information from the electrodes using the LEDs on the display. See page 4 at the bottom left if you are interested. http://mydigimag.rrd.com/publication/?i=220714

These have been around a long time and have not really changed. They have always been conductivity based, but they are made up of a water column with electrodes inserted at points along the column. If you are between points, you only know you are above one and below another. You don't know exactly where in between those two points you are. We have a white paper that talks about optimizing your control loop.

Maybe the new models of hydrastep use conductivity, but not the old ones, as they use the optical path to either deflect a beam of light or not. This is a discrete element type of sensor with a number of elements, so the operator only has an approximate actual level. Other drum level sensing is done based on differential pressure between an outside reference column filled with condensate, and the internal column that is the drum level actual.